Most discussions on improving health focus on two main factors:  exercise and proper nutrition.  Planning to eat healthier means understanding the role of the variety of foods in providing all the vitamins and minerals needed to support the functions of a strong, healthy body.  There are even “Recommended Daily Allowances (RDAs) to help us learn the baselines of what we need.

Often, becoming overzealous about meeting every single one of the guidelines leads to the instant gratification approach of using vitamin and mineral supplements to quickly and easily meet those requirements — a nutritional “easy button,” if you will.   But there are issues with this approach.  While whole foods provide a full complement of vitamins, minerals, enzymes, amino acids, and fiber, for all-around health, a small pill can only provide a limited replica of that nutritional value.

In addition, there are some serious cautions that may not be immediately evident.   In our enthusiasm to hurry up and get healthy, or be proactive about disease prevention, we may assume that “if one is good, three must be better” — and that can unknowingly create potential problems for your health, says Dee Sandquist, a registered dietitian, and spokesperson for the Academy of Nutrition and Dietetics.

Top Ways Supplements Can Cause You Harm

  • Lack of FDA Review:   Notably, the U.S. Food and Drug Administration, which you might assume would oversee making sure that our dietary supplements are safe to consume, does not have the authority to review supplement products for safety and effectiveness before they are provided commercially.   They are only notified for review, not approval, if there is a new ingredient in a supplement, to check for safety.   Product manufacturers ‘must produce supplements in a quality manner, and ensure that they do not contain contaminants or impurities, and are accurately labeled, according to “Good Manufacturing Practice.”  Only if there is a serious problem with the product are manufacturers required to report the “adverse events” to the FDA, which can then take products off the market if they are unsafe, or if the claims made for the product are misleading.
  • 1994 Dietary Supplement Health and Education Act (DSHEA):  This Act was intended to establish industry guidelines and procedures.   Yet for a full 13 years after its passage, manufacturers didn’t even have to inform the FDA of any product problems.   An updated law in 2007 amended that non-requirement, and as a result, in 2008 and 2009, the FDA received 1359 problem reports from manufacturers, and another 602 from consumers and health professionals.  However, because the FDA generally doesn’t make those reports available to the public, it’s difficult for even conscientious consumers to learn of past problems with a product.
  • Poor Quality Control:  While Good Manufacturing Practices are generally observed, the lab or facility in which a product is produced doesn’t tell the full story.  Manufacturers in for-profit businesses need to control production costs in order to competitively price their products for market share.  As a result, many turn to China, a major supplier of raw supplement ingredients, even though it’s widely known that often, their products are contaminated, or poorly monitored for ingredients.  Because of poor quality control, consumers have unwittingly used products contaminated with heavy metals, pesticides, or prescription drugs; in one case, a multi-vitamin was found to contain “more than 200 times the labeled amount of selenium and up to 17 times the recommended amount of chromium.”  While there’s no real way for the consumer to monitor the product quality, it’s safe to advise buyer beware of an extremely low price, as that may indicate corners cut, and quality compromised, throughout the process.
  • Mixing with Medicines:  In addition to individual supplement ingredient concerns, one of the most common problems is that many consumers don’t consider the impact of all their medications and/or supplements combined.   Robert Mozersky, Medical Officer at the FDA, notes that “supplements can increase or decrease the effect of your medication, which can cause serious problems.”  With changes in absorption rates or metabolism of the medication, combining products can affect potency and effectiveness.  For example, St. John’s Wort, a natural supplement, can significantly reduce the effect of drugs for heart disease, HIV/AIDS, or depression, and birth control pills are less effective because of the combination.  Not knowing that ginkgo biloba, aspirin and Vitamin E are all blood thinners can cause a serious risk of internal bleeding or stroke, if they are taken together.  In fact, the National Health and Nutrition Examination Study for the Centers for Disease Control and Prevention (2005 – 2008) found that ‘”34% of participants — representing over 72 million Americans — were taking some kind of dietary supplement along with a prescription medication.”   And many supplements can impact medications involved with surgical procedures, so you want to be sure to let your healthcare professional know every supplement you are taking, in addition to any prescription drugs.
  • New Products Don’t Mean Better Proven Results.  Because it’s such a large industry, the supplement business attracts new manufacturers and new products all the time.  Americans spend over $28 Billion annually on dietary supplements, so there is a huge financial incentive for new products.  With multiple company names and product formulations on every vitamin shelf in grocery, health food, and drug stores, it’s almost impossible to be able to do effective consumer research before purchase.  According to the Natural Medicines Comprehensive Database, of the 54,000 dietary supplement products in their database, “only about a third have scientifically supported safety and effectiveness evidence,” and “almost 12% have been linked to safety concerns or issues with product quality.”
  • False Claims.  Although it’s illegal for companies to claim any specific health benefit or cure for supplements, heavy advertising, vague product labeling and outright deception can further confuse consumers.  The Federal Trade Commission has filed or settled 30 cases against supplement marketers for claims that are clearly out of bounds.  The advent of online marketing has only increased the likelihood of abuse, as there are so many more providers who may be operating under the radar of any semblance of product quality control.   In addition, frequent product re-formulations only serve to increase the potential for confusion.
  • Beware the Results of “Research Studies.”  Many of the available “research” results are based on observational rather than rigid test protocol procedures.   That’s why we often read about a “new study” that shows promise for disease prevention through vitamin supplementation.  Reports of Omega-3 fatty acids to prevent strokes or other cardiovascular events, Vitamin D to ward off depression, antioxidants like Vitamins C and E as prevention against heart disease, cancer, and even Alzheimer’s disease all help promote the do-it-yourself approach to managing our health.  Observational studies may not fully account for variables among individuals, and as Dr. JoAnn Manson, Chief of Preventive Medicine at Brigham and Women’s Hospital and Professor of Medicine at Harvard Medical School has found, “Often the enthusiasm for these vitamins and supplements outpaces the evidence.  And when the rigorous evidence is available from randomized controlled trials, often the results are at odds with the findings of the observational studies.”

Common “Problem” Supplements

While each of these vitamins provides natural value to a healthy diet, some of the more serious outcomes observed with exceeding recommended dosages of common vitamin supplements may include:

Vitamin A:   While Vitamin A is found naturally in many foods, it’s the high intake through supplements that can cause dry, scaly skin, headaches, appetite loss, vomiting, joint problems, bone pain, and liver conditions.   In severely high doses, it can lead to birth defects, and disorders of the nervous system.  Beta-carotene, a form of Vitamin A, was thought to be a cancer preventer — but in the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study, researchers discovered that “male smokers who took beta-carotene supplements were 18% more likely to develop lung cancer and 8% more likely to die” than the subjects who didn’t supplement.   Gerald Mullin, the Johns Hopkins Hospital Director of Integrative Gastrointestinal Nutrition Services, has treated patients with liver fibrosis due to overdoses of Vitamin A — “people don’t know it can be dangerous — they think it fights infections.”

Vitamin C:  Too much Vitamin C can cause nausea, diarrhea, and stomach cramps.  While it is a water-soluble vitamin, with excesses usually excreted naturally, according to, additional effects can include headaches, bloating, kidney stones, insomnia, vomiting, and heartburn.  While the natural form of the vitamin in foods can help boost immune function, there’s no evidence that Vitamin C pills can prevent a cold.

Vitamin D:  It sounds benign when described as “the Sunshine Vitamin,” with important benefits for overall body health, effective in treating bone diseases like rickets, osteoporosis, brittle bones, and some skin conditions.  While the body can generally regulate the amount of Vitamin D acquired from sun exposure, excessive supplement intake can lead to reduced kidney function, nausea, muscle weakness and bleeding.   More than 4000 IU per day could lead to heart problems.

Vitamin E: While once considered a promising cancer fighter, it’s also known that Vitamin E can interfere with anticoagulant medication, and potentially increase the risk of internal bleeding and strokes.   In fact, follow-up studies found that high doses can be counterproductive.   The National Cancer Institute funded a study in 2001 to test the theory that Vitamin E could reduce the instance or prostate cancer — what they found was that men who took Vitamin E were 17% MORE likely to develop the disease.

The general consensus in the medical community is that vitamin and mineral supplementation is best done through building a diet of varied foods that can provide a wide range of nutritional elements, without the risk of exceeding recommended safe levels.   Dr. Manson concludes: “Fruits, vegetables, fish, and other healthy foods contain nutrients and other substances not found in a pill, which work together to keep us healthy.  Taking certain vitamins or minerals in higher-than-recommended doses may even interfere with nutrient absorption, or cause side effects.”

And of course, there are some common-sense precautions consumers can take as well:  check with your medical professional or pharmacist for their recommendations; look for “USP Verified” as an indication that the manufacturer willingly meets standards of quality, purity, and effectiveness of their products; research in reputable medical/science or consumer resources for information relevant to your own needs.   A healthy dose of skepticism can also be your best defense — remember that while supplements can indeed be an assist to your health, they should not replace healthy foods.  The approach to long-term good health is a “marathon” of regular daily good habits, rather than a “sprint” with a quick fix in a capsule.


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